Discard Page Contents

Discards the entire contents of a given linear memory range.
This function is used when a memory object (such as a data
structure) that occupies a given area of memory is no longer
needed, so that the area will not be paged to disk
unnecessarily.  The contents of the discarded region will be
undefined.

Call With:

   AX     = 0703h
   BX:CX  = starting linear address of pages to discard
   SI:DI  = size of region to discard (bytes)

Returns:

   if function successful
   Carry flag= clear

   if function unsuccessful
   Carry flag= set
   AX     = error code
           8025H   invalid linear address (range
                   unallocated)

Notes:

o  Partial pages and locked pages will not be discarded.